For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningInterior Windnoise
Warning: Refer to Assistant Driving Warning in the Preface section.
Interior windnoise is not heard when the window is lowered. Interior
windnoise is caused by the air leaving the inside of the vehicle
through a seal or a seam.
Tape over the relief valves to cause added air pressure wi ...
Braking
Braking action involves perception time and reaction time. Deciding to push the
brake pedal is perception time. Actually doing it is reaction time.
Average driver reaction time is about three-quarters of a second. In that time,
a vehicle moving at 100 km/h (60 mph) travels 20m (66 ft), which co ...
Service Publications Ordering Information
Service Manuals
Service Manuals have the diagnosis and repair information on the engines, transmission,
axle, suspension, brakes, electrical, steering, body, etc.
Service Bulletins
Service Bulletins give additional technical service information needed to knowledgeably
service General Motors c ...